It may sound like something delicious on a hot summer day, but it is actually the new standard sampler recommended by the EPA and USGS. This phrase refers to our modified kick net with 60” handles in 500 mm Nitex® mesh (425-M53 or 425-N53). Also termed a “Slack sampler,” it has sold widely to customers throughout the U.S.A. USGS customers generally also order a 47-E60 500 mL Dolphin™ bucket in 504 mm SS mesh and 47-E99 guard rails.
1. Position net(s) in flowing water, using stakes
2. After placing net in water, frequently remove organisms and debris to prevent clogging of the net mouth.
3. Specify the time of study (1 to 3 hours is recommended) and use the same time length at each station.
4. Sampling between dusk and 1 A.M. is best.
5. Drift intensity measures the total number and biomass of organisms drifting past a given station.
1. Attach a stout line to the top swivel line.
2. Tow net slowly, regulating depth by speed.
3. Tie on a tow weight for horizontal sampling
1. While setting and sampling with the surber, be careful not to disturb the substrate upstream from the sample area. This could cause organisms from outside the sample area to be caught in the net.
2. Set the surber with the net upright, water flowing into the net. The water cannot flow over the top of the net or some of the sample could be lost downstream.
3. Set the open frame on the stream bottom, marking off the area to be sampled.
4. Being careful not to disturb the sample area in the frame, block off any gaps where water can run under the frame or the net. Use surrounding substrate materials. (In a stronger current you may have to hold the surber in place for sampling.)
5. Carefully turn over and hand-rub all the stones inside the frame to dislodge any organisms that may be clinging to them. Before discarding them, examine each one by eye. Sometimes insect larvae and pupae cling very tightly. Make sure everything gets caught in the sampler net.
6. Stir the remaining gravel and sand with your hands or sticks to a depth of 5 to 10 cm. This will dislodge bottom-dwelling organisms. Hand-pick snails and other “heavier” organisms that are not picked up by the current.
7. Keep an eye on the net. If it becomes too clogged, sample can be lost from backwash.
8. On shore, invert the net into a sample container or a sieve with the same or smaller mesh size. Rinse down the net. Carefully examine the net for clinging organisms. Remove with forceps.
9. Rinse down the sampler after each use. Let it dry completely before storage.
These are professional nets for serious field work. We use genuine Nitex® cloth and multifilament nylon. But the proof is in the pudding, or – in our case – the muslin, which is more manageable under water than nylon and polyester. It moves as you move, even when wet, and protect from snags and tears!